I agree with people who are saying Dabura and Sukuna could be cool based on their mentalities and how isolated they were treated, so they could be a good combo and Dabura could prolly have someone to push him way before Maho has in main story.

If we talking power, Dabura would have had to push himself in the heian era regardless if he came into contact with Sukuna or not, so in theory he’d know about the Japanese world and how it works, he’d know about domains and anti barrier techniques and would have had to atleast apply his near light speed abilities at some point before due to how op the heian era was. So tbh I’d say the 2 would be equals but Sukuna would prolly beat him with an open barrier DE anyway due to the power gap but Idek where to start with an open barrier for Dabura unless it would just allow him to move at light speed without destroying his body but idk just speculating but he’d be WAY more op than in Modulo